SIMBAD references

2021MNRAS.502.6117C - Mon. Not. R. Astron. Soc., 502, 6117-6139 (2021/April-3)

A faint companion around CrA-9: protoplanet or obscured binary?

CHRISTIAENS V., UBEIRA-GABELLINI M.-G., CANOVAS H., DELORME P., PAIRET B., ABSIL O., CASASSUS S., GIRARD J.H., ZURLO A., AOYAMA Y., MARLEAU G.-D., SPINA L., VAN DER MAREL N., CIEZA L., LODATO G., PEREZ S., PINTE C., PRICE D.J. and REGGIANI M.

Abstract (from CDS):

Understanding how giant planets form requires observational input from directly imaged protoplanets. We used VLT/NACO and VLT/SPHERE to search for companions in the transition disc of 2MASS J19005804-3645048 (hereafter CrA-9), an accreting M0.75 dwarf with an estimated age of 1-2 Myr. We found a faint point source at ∼0.7-arcsec separation from CrA-9 (∼108 au projected separation). Our 3-epoch astrometry rejects a fixed background star with a 5σ significance. The near-IR absolute magnitudes of the object point towards a planetary-mass companion. However, our analysis of the 1.0-3.8µm spectrum extracted for the companion suggests it is a young M5.5 dwarf, based on both the 1.13-µm Na index and comparison with templates of the Montreal Spectral Library. The observed spectrum is best reproduced with high effective temperature (3057+119–36K) BT-DUSTY and BT-SETTL models, but the corresponding photometric radius required to match the measured flux is only 0.60+0.01–0.04 Jovian radius. We discuss possible explanations to reconcile our measurements, including an M-dwarf companion obscured by an edge-on circum-secondary disc or the shock-heated part of the photosphere of an accreting protoplanet. Follow-up observations covering a larger wavelength range and/or at finer spectral resolution are required to discriminate these two scenarios.

Abstract Copyright: © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society

Journal keyword(s): techniques: image processing - planets and satellites: formation - planet-disc interactions - protoplanetary discs

VizieR on-line data: <Available at CDS (J/MNRAS/502/6117): spectra.dat sp/* images.dat fits/*>

Simbad objects: 23

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2021.12.05-02:42:19

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